Methylene synonyms

The true nitrile of malonic acid is methylene cyanide, CH 2 (CN) 2, which is obtained by distilling a mixture of cyanacetamide and phosphorus pentoxide.

A larger and more important series of condensations may be grouped together as resulting from the elimination of the elements of water between carbonyl (CO) and methylene (CH 2) groups.

Pyrrol is readily converted into pyridine derivatives by acting with bromoform, chloroform, or methylene iodide on its potassium salt, t3-brom-and O-chlorpyridine being obtained with the first two compounds, and pyridine itself with the last.

Conversely, by heating protocatechuic acid with potash and methylene iodide, piperonylic acid was regained.

These results show that piperonylic acid is the methylene ether of protocatechuic acid.